Which of the following statements is correct? (i) Arctic tern travels from Antarctic to Arctic in winter. (ii) Monarch butterflies travel from Canada to Mexico during the winter season. (iii) Salmons swim long distances to reach sea to lay eggs. (iv) Siberian cranes come to India during winter.

• A.  (ii) and (iii) only  
• B.  (ii) and (iv) only
• C.  Law of multiple proportion
• D.  (i) and (ii) only